Departamento de Biología de la Conservación, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Baja California, Mexico.
Department of Environmental Science Policy and Management, University of California, Berkeley, CA, USA.
New Phytol. 2011 Sep;191(4):1006-1017. doi: 10.1111/j.1469-8137.2011.03771.x. Epub 2011 May 24.
Although there is increasing evidence of the temporal correlation between photosynthesis and soil CO(2) efflux, no study has so far tested its generality across the growing season at multiple study sites and across several time scales. Here, we used continuous (hourly) data and applied time series analysis (wavelet coherence analysis) to identify temporal correlations and time lags between photosynthesis and soil CO(2) efflux for three forests from different climates and a grassland. Results showed the existence of multi-temporal correlations at time periods that varied between 1 and 16 d during the growing seasons at all study sites. Temporal correlations were strongest at the 1 d time period, with longer time lags for forests relative to the grassland. The multi-temporal correlations were not continuous throughout the growing season, and were weakened when the effect of variations in soil temperature and CO(2) diffusivity on soil CO(2) efflux was taken into account. Multi-temporal correlations between photosynthesis and soil CO(2) efflux exist, and suggest that multiple biophysical drivers (i.e. photosynthesis, soil CO(2) diffusion, temperature) are likely to coexist for the regulation of allocation and transport speed of carbon during a growing season. Future studies should consider the multi-temporal influence of these biophysical drivers to investigate their effect on the transport of carbon through the soil-plant-atmosphere continuum.
虽然越来越多的证据表明光合作用和土壤 CO2 排放之间存在时间相关性，但迄今为止，还没有研究在多个研究地点和多个时间尺度上检验其普遍性。在这里，我们使用连续（每小时）数据，并应用时间序列分析（小波相干分析）来识别光合作用和土壤 CO2 排放之间的时间相关性和时滞，研究了来自不同气候和草原的三个森林。结果表明，在所有研究地点的生长季节中，1 到 16 天的时间间隔存在多时间相关性。在 1 天的时间间隔内，相关性最强，与草原相比，森林的时间滞后更长。多时间相关性在整个生长季节并不连续，并且当考虑土壤温度和 CO2 扩散率变化对土壤 CO2 排放的影响时，相关性会减弱。光合作用和土壤 CO2 排放之间存在多时间相关性，这表明在生长季节期间，多个生物物理驱动因素（即光合作用、土壤 CO2 扩散、温度）可能共同存在，以调节碳的分配和运输速度。未来的研究应该考虑这些生物物理驱动因素的多时间影响，以研究它们对通过土壤-植物-大气连续体运输碳的影响。
